A numerical study of the thermal performance of an impingement heat sink-fin shape optimization

This paper presents the results of a numerical analysis of the performance of an impingement heat sink designed for use with a specific blower as a single unit. These self-contained heat sink/blower units, which cause impingement type flow on the heat sink fins, are now commonly used for desktop microprocessors. One of the objectives of this study is to examine the effect of the shape of the heat sink fins, particularly near the center of the heat sink, on the thermal performance of the package. The pressure gradient at the center of the heat sink, near the base, tends to be high. It significantly reduces the airflow, and hence, transport in that region. Different fin shapes and airflow rates have been studied with the objective of searching for an optimal heat sink design that would improve the thermal performance without increasing the pressure drop across the heat sink. Parallel plate fins have been studied by removing fin material from the region near the center of the heat sink along the length and height of the fins. Seventeen different designs have been compared, and an " optimum" heat sink shape is reported that results in a lower operating temperature and pressure drop. It is found that removal of fin material from the central region of the heat sink enhances the thermal as well as hydraulic performance of the heat sink.